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=head1 pgestraier - search Hyper Estraier indexes from PostgreSQL |
=head1 pgestraier - PostgreSQL full-text search using Hyper Estraier |
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This package is essentially PostgreSQL C function which calls Hyper Estraier |
This package is essentially composed of two different parts: |
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API and returns results in user defined format. |
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=over 4 |
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=item search function |
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PostgreSQL function to search Hyper Estraier full-text index, using |
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full-text queries and attribute filtering to return user-specified |
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table of results. |
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This function can mimic SQL C<LIMIT>, C<OFFSET> and C<ORDER BY> |
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functionality much faster than using those SQL constructs on search |
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results. |
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=item trigger function |
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PostgreSQL trigger function to keep Hyper Estraier in sync with PostgreSQL. |
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It triggers after insert, update or delete and update full-text index |
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accordingly. |
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=back |
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Both functions are written in C, while test framework and supporting |
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utilities are written in perl. |
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You can use just one of those functions. If you want just to search existing |
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Hyper Estraier index or generate it off-line (after nightly batch jobs, for |
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example), just use search function. |
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On the other hand, if you want just to keep your Hyper Estraier index in |
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sync with PostgreSQL data, you can use just trigger function to achieve that. |
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=head1 Why is it written? |
=head1 Why is it written? |
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Aside from providing single API to query your RDBMS and full text index |
Aside from providing single query language (SQL) to RDBMS and full text index |
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(using any language that has PostgreSQL client libraries), real power is |
(using any language that has PostgreSQL client libraries), real power is |
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hidden in ability to join results from full text index and structured data |
hidden in ability to join results from full text index and structured data |
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in RDBMS. |
in RDBMS. |
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For simple real-life example which address problem |
For simple real-life example which address problem |
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I<where like '%foo%' is slow> |
C<< WHERE name LIKE '%foo%' OR surname LIKE '%foo%' >> |
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see L<Tutorial>. |
is slow see L<Tutorial>. |
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=head1 How to install |
=head1 How to install |
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Installation should be simple. However, you will have to have following |
Installation should be simple. However, you will have to have following |
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software already installed before you try this function: |
software already installed before you try this functions: |
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=over |
=over |
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=item * |
=item * |
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PostgreSQL (tested with versions 7.4 and 8.0) with development libraries |
PostgreSQL (tested with versions 7.4, 8.0 and 8.1) with development libraries |
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=item * |
=item * |
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Hyper Estraier (tested with various versions, recommended 1.2.4 of newer) |
Hyper Estraier (tested with various versions, recommended 1.2.4 or newer) |
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with development headers |
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=item * |
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working C compiler (tested with gcc) |
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=back |
=back |
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To run tests you will also need: |
If you want to use helper script to create consistency triggers to keep |
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Hyper Estraier in sync with PostgreSQL database, you will also need: |
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=over |
=over |
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=item * |
=item * |
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perl modules C<DBI>, C<DBD::Pg>, C<Test::More> and optionally C<Search::Estraier> |
perl modules C<Search::Estraier>, C<DBI> and C<DBD::Pg> |
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=back |
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To run tests you will also need: |
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=over |
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=item * |
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perl module C<Test::More> |
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=item * |
=item * |
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See also included file C<test.sql> for more examples of usage. |
See also included file C<test.sql> for more examples of usage. |
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=head1 Usage of pgest from SQL |
=head1 Usage of search function pgest from SQL |
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C<pgest> PostgreSQL function tries to mimic usage of normal database tables (with support for attribute filtering, limit and offset) in following way: |
C<pgest> PostgreSQL function tries to mimic usage of normal database tables (with support for attribute filtering, limit and offset) in following way: |
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index grows bigger, you might consider using node API to remove overhead of |
index grows bigger, you might consider using node API to remove overhead of |
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database opening on each query. |
database opening on each query. |
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=head1 Usage of trigger function pgest_trigger from SQL |
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Let's first say that I really suggest that you use C<dbi-index.pl> helper script to |
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create triggers because it already supports following steps automatically: |
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=over |
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=item begin transaction |
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Transaction is needed to catch updates which might happen while creation |
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of full-text index is in progress (and on huge collections this can take a while, |
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just like normal index creation in PostgreSQL). |
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=item insert all existing data in full-text index |
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This will be done directly from PostgreSQL database to Hyper Estraier index. |
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This is somewhat faster than waiting for trigger to fire for each existing |
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row. |
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=item create insert, update and delete triggers |
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Which will keep data in sync later |
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=item commit transaction |
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=back |
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If you still want to do that manually, you will need to know format of |
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C<pgest_trigger> function: |
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CREATE TRIGGER pgest_trigger_insert AFTER INSERT |
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ON table FOR EACH ROW |
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EXECUTE PROCEDURE pgest_trigger( |
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-- node URI, login and password |
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'http://localhost:1978/node/trivia', 'admin', 'admin', |
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-- name of primary key column |
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'id', |
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-- names of all other columns to index (one or more) |
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'column', 'another_one', 'and_another' |
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) |
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You have to create triggers for C<UPDATE> and C<DELETE> in similar way. |
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=head1 Who wrote this? |
=head1 Who wrote this? |
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Hyper Estraier is written by Mikio Hirabayashi. |
Hyper Estraier is written by Mikio Hirabayashi. |